Jason Pollard, City of Ottawa Forester

“A healthy diverse forest will help to ensure that trees and forests are best able to withstand climate stressors.” Jason Pollard, forester with the City of Ottawa, describes the state of our tree canopy, threats from invasive species and climate change, and how residents can help the City grow a healthy and resilient forest.

Photos: Chris Osler

Q.1. Was there a specific time or event in your life that sparked your interest in becoming a forester?

Looking back it was my time spent outside as a child that built my interest in the natural environment. I also have a family member who is a forester and helped set a path to follow toward a career in forestry.

Q.2. From your perspective, what are the contributions made by trees that make them so important and valuable?

Trees are present in many aspects of our daily lives and provide a number of environmental, aesthetic and functional benefits. Trees are valued for a sense of space and community, for environmental contributions such as pollution abatement, oxygen production and wildlife habitat, trees contribute to visual landscapes and add aesthetic values to communities, and trees can function in storm water abatement, shade to reduce home energy consumption and contribute to carbon sequestration. To ask different people a similar question would result in different but interesting and unique answers.

Q.3. How would you describe the state of trees in Ottawa’s urban core?

Trees in Ottawa’s urban core are challenged by a growing and changing urban environment. Growth, construction and intensive land uses in an urban area present challenges to trees. This changing urban landscape is an important reminder that planning and accommodations for trees are important considerations for tree and forestry professionals and professionals in other disciplines such as engineering, construction and urban planning.

Q.4. In 2012 it was reported that Ottawa’s tree canopy was made up of 25% ash trees. What percentage of those ash trees have died or will die because of the Emerald Ash Borer? In actual numbers, how many ash trees have died or are projected to die?

25% of Ottawa’s forest cover in both urban and rural areas is estimated as ash. Expectations based on experience to date indicate that all ash trees will be attacked and killed by emerald ash borer (EAB), although there may be some trees that escape or those treated with pesticide that survive. Questions remain about how the forest will recover in natural areas and how ash will continue to regenerate naturally. Total numbers of trees are difficult to estimate, especially in forested areas, but many thousands of ash trees are dying and will continue to be attacked and killed by EAB.

Emerald ash borer markings.

Q.5. What happens to the ash trees once they are cut down by the city?

In the early stages of ash tree removals for EAB in Ottawa, a number of small trials were completed with private companies on the possible future use of ash with the goal of creating useable wood products from EAB-killed trees. More recently, the City has worked with local companies including a sawmill so that ash wood is available for use in future City facilities. Currently, wood from ash trees killed by EAB is being processed for use in the light rail transit stations for things such as wall and ceiling features or items such as benches and windscreens.

Q.6. Besides the Emerald Ash Borer, what are the major threats to trees in Ottawa?

Climate change and invasive alien species such as emerald ash borer or Asian long-horned beetle continue to be the major threats of concern to forestry professionals. These things are difficult to predict and plan for, however a diverse and healthy forest through tree planting, tree maintenance and tree protection will be more resilient to disturbance from climate change or invasive species.

Q.7. What are the city’s priorities in terms of protecting and caring for trees?

City of Ottawa Forestry Services is mandated with maintaining, protecting and enhancing Ottawa’s forest cover. In particular, over the last number of years significant tree planting efforts have been a major focus of the City’s emerald ash borer response.

Q.8. What effect, if any, has climate change had on Ottawa’s urban trees?

Local effects from climate change to date have been variable and difficult to predict. Hotter and drier summers, warmer winters, changing weather and precipitation patterns, and increased intensity or frequency of storms are all associated with climate change and can all have variable and unpredictable effects on trees and forests. Planning for climate change in forestry is difficult but ensuring a healthy diverse forest will help to ensure that trees and forests are best able to withstand climate stressors.

Q.9. Besides planting trees on their property, how can citizens in Ottawa help protect, care for and promote trees in Ottawa?

The City of Ottawa has helped set an example through maintenance, protection and planting programs. In Ottawa and most cities, the land area owned privately is greater than that owned by the City. As a result, we rely on citizens to contribute to our goal of growing a healthy forest. Watering, proper pruning, adequate tree protection during construction, and new tree planting are all activities that the public can consider on their own properties to contribute to a healthy forest for Ottawa.

Q.10. Finally, do you have a favourite tree in Ottawa? If so, what species of trees is it and where is it located?

An area that is significant and unique to Ottawa is the Dominion Arboretum in the Central Experimental Farm. This federal property helps to raise awareness and educate the public about trees in Ottawa and shows a history and diversity of trees and forests across Canada and temperate regions of the world. It’s a great place to expand your knowledge and awareness of trees and forests. The area with maple trees in the arboretum provides interesting colour in the fall. In particular, sugar maple has great fall colour and great cultural significance.